The present invention relates to a seat belt retractor.
German patent application 100 13 870.5 teaches a seat belt retractor having a belt reel that is rotatably mounted on a frame and on which the seat belt can be wound and unwound. A motive spring biases the belt reel in the winding direction. An electric motor adjusts the spring force of the motive spring and/or a torque can be produced for tightening the seat belt. A clutch transmits torque to the belt reel. The clutch comprises a spring element that can be deformed by the torque and which, when deformed, brings the clutch into an engaged state.
The present invention provides a seat belt retractor having a clutch. A spring element, whose deformation brings the clutch into an engaged state, is held at one end of the spring by a holding device actuated by inertial force, in order to initiate its deformation, while the torque produced by a drive device acts upon the other end of the spring element. The deformation of the spring element is thus achieved by mere mechanical means to bring the clutch into the engaged state.